Method and apparatus for forming glass



July 23, 1963 R. G. ORMSBY ETAL 3,098,948

METHOD AND APPARATUS FOR FORMING GLASS Filed June 9, 1960 J/ 4/ 23 .nin

ll-lulllll" lul Y 54 l 'Nl l kc y I5 /Au/f/vro/es rroR/vEY United States Patent O C 3,093,948 METHOD AND APPARATUS FOR FRMING GLASS Raymond G. Ormsby and Frederick .L Trementozzi, Corning, N .Y., assigner-s to Corning Glass Works,

Corning, N.Y., a corporation of New York Filed .lune 9, 1960, Ser. No. 35,007

2 Claims. (Cl. 317-6) The present invention relates to the formation of cathode ray tubes, such as television receiving tubes having generally rectangular face plates. It has heretofore been proposed to press the funnel portions of such tubes and to provide beam clearance at the junction of the neck and funnel by pressing channels therein in four places located to serve as beam passages to the four corners of the face plate.

As is well known that the larger sizes of cathode ray tube funnels are for the most part being produced centrifugally, thus the problem of forming the beam clearance grooves coincidental with the centrifuging of the tube funnel from a charge of molten glass is presented.

According to the invention such problem is solved by the replacing of a conventional plain tipped distributor with one having four beam clearance forming protuberances or bosses and adapted to be introduced into the funnel neck wall and after being circumferentially positioned to register the grooves produced by it with the four corners of the funnel. To positively insure that this exact registry will be achieved without having to resort to the use of a cumbersome mechanical coupling between the funnel mold drive shaft and the distributor, the rotation of the distributor is effected, by a separate power source, through the medium of a synchro transmitter driven off the mold rotating shaft and a synchro torque receiver which, through the medium of a torque amplifier, appropriately controls the torque amplifier to attain this end.

For a better understanding of the invention reference is now made to the accompanying drawing in which:

FIG. r1 comprises an elevation, partly in section, and partly diagrammatically of a glassworking system such as shown in U.S. Patent No. 2,662,346, and embodying the invention.

AFIG. 2 is a top plan View of a funnel-tube formed in accordance with the invention, by apparatus such as shown in FIG. 1.

FIG. 3 is a diagrammatic view illustrating the inner structural features of a power amplifier such as embodied in the showing of FIG. 1.

Referring tothe drawing in detail, the numeral 11 designates a fragment of a mold in which a glass funnel-tube, adapted to take a rectangular face plate, may be centrifuged in a conventional fashion, as taught for example in U.S. Patent No. 2,662,346 and employing a mold such as disclosed in Patent No. 2,662,347, both granted to J ames W. Giffen, December 15, 1953. As indicated, mold 111 is adapted to be rotated by a shaft 12 through miter gears 13 and 1.4 to centrifuge a charge of glass 26, deposited therein as described in the first of the above patents. A distributor 17 is caused to enter the mold in an understood manner to impart to the neck of the funneltube formed therein the desired contour and carriers four bosses such as 18 therein to form beam clearance grooves 19 (FIG. 2) in the tube thereof at its junction with the funnel.

Attached to the drive shaft 2t) for mold 11 is a gear 15 in mesh with a gear 16 carried by the shaft of a synchro transmitter 21 electrically coupled by a cable 22 to a synchro receiver 23 supplied with suitable alternating current at terminals A.C. As shown in FIG. 3, drum shaft 37 of the torque amplifier 30 and its drum 39 are 3,098,948 Patented` July 23, 1 963 driven by a motor 50 (FIG. 1) through the medium of a suitable coupling S1 connected to shaft 37 and drum .40 is adapted to be driven off shaft 37 through the medium of gears 43 and 44 in mesh with one another and fixed to shafts 37 and 38 respectively. The shaft 24 of torque receiver 23, which is identical to the synchrotransmitter 21, carries a drive pinion 25 in mesh with drive gears 31 and 32 of the torque amplifier 30. Gears 3l and 32 respectively are connected through bands 33 and 34 helically wound about drums 39 and 40 and connected respectively to drive gears 35 and 36. Gears 31, 32, 35 and 36 are free to rotate about shafts 37 and 38 respectively carrying the drums 39 and 40 about which the helical bands 33 and 34 are wound. The output shaft 41 of the torque amplifier 30 is adapted to be driven by a pinion 60 in mesh with gears 35 and 36, and in turn drives the distributor shaft 41' through the medium of gears 53 and 54 (FIG. l).

As will be understood, the rotary positions of the distributor 17 and mold 11 are such normally as to bring the protuberances or bosses such as 18 of the distributor 17 into the proper positions for alignment or registry with the corners of the large open end of the mold 11, which is of the rectangular proportions to provide for centrifuging funnel-tubes adapted for use with face plates providing a 4:3 rectangular viewing area.

The relative rotary posiitons of the mold and distributor are maintained as the mold goes through its centrifuging cycle in a fashion which will now be explained.

As will be appreciated from the showing of FIG. 3, the torque receiver 23 will operate at the speed of and in synchronism with the torque transmitter 21 and, obviously if it had enough power and if the bands 33 and 34 were of suicient rigidity would directly mechanically rotate the distributor 17 through the medium of its pinion 25, gears 31, 32, band 33, gear 35 and pinion 60 of the torque amplifier 30. This drive cannot be relied upon however, since the torque of receiver 23 is minor compared to that needed to rotate the distributor 17. The drive is actually effected by motor 50 which can only transmit torque to band 33 or 34 when the position of rotation of the transmitter 2.1 tends to deviate from that of the torque receiver. At such time a frictional coupling between drum 39 or 40 and the motor 5t) is established through the appropriate one of the bands 33 and 34 to correct the condition. The torque receiver 23 thus simply maintains the coupling between one or the other of the spiral bands of the torque amplifier 30 and its drum as is necessary to obtain synchrous rotation of the distributor 17 with the mold 11. Drum 40 in the present example drives the distributor in a corrective direction at those times that the receiver tends to lead with respect to the mold. To reduce any tendency to hunt, adrum 55 is secured to the distributor shaft 41 and is frictionally engaged by a strap 52 held under slight tension by a turn screw 56.

It will thus be seen that with a coupling as provided, when the mold begins to turn it displaces the synchro transmitter from a zero reference position. The synchro transmitter thus transmits a signal to the receiver which indicates that a possible error exists between the receiver and transmitter. The torque is produced at the receiver which is proportional to the error, in degrees, between the transmitter and receiver. This output torque of the receiver is fed to the torque amplifier which provides the power from the motor 50 necessary to maintain the position of the distributor in proper circumferentail alignment with the mold.

A power amplifier of this general type is well known and fully shown and described in the November 24, 1958, issue, pages 60 and 6l, of Product Engineering, McGraw- Hill Magazine of Design Research and Development.

What is claimed is:

'1. The combination with a driven shaft of a second shaft to be driven in synchronism therewith, a synchrotransmitter coupled with said driven shaft for producing an electrical output proportional to the velocity of rotation ot the driven shaft, a synchro-receiver directly connected to the electrical output of said synchro-transmitter for producing a mechanical torque output proportional to such electrical output, a mechanical torque amplifier directly coupled with the output of said synchro-receiver and having motor means for mechanically amplifying such output, such amplifier producing an amplied mechanical torque output proportional to the output of said synchro receiver and directly coupled with said second shaft.

2. In combination with a mechanical torque amplifier having a control input shaft, an output shaft and motor means for supplying to the output shaft an amplified mechanical torque proportional to a mechanical torque supplied to the control input shaft; a rotatively driven shaft, a synchro-transmitter coupled with said driven shaft for producing an electrical output proportional to the velocity of rotation of such shaft, a synchro-receiver directly connected to the electrical output of said synchrotransmitter for producing a mechanical torque output proportional to such electrical output and supplied to the control input shaft of said amplifier, and a second driven shaft coupled with the output shaft of said amplifier, whereby such second driven shaft is rotated in synchronism with said rst driven shaft.

References Cited in the tile of this patent UNITED STATES PATENTS 2,306,054 Guyer Dec. 22, 1942 2,410,345 Hinkley Oct. 29, 1946 2,696,699 Giften Dec. 14, 1954 2,795,747 Wellington et al June 11, 1957 2,861,394 Ruft Nov, 25, 1958 3,010,051 Lindemann Nov. 21, 1961 FOREIGN PATENTS 806,761 Great Britain Dec. 31, 1958 820,181 Great Britain Sept. 16, 1959 OTHER REFERENCES Product Engineering, vol` 29, November 24, 1958, pp. 60 and 61, McGraw-Hill Publ. Co., N Y. 

1. THE COMBINATION WITH A DRIVER SHAFT OF A SECOND SHAFT TO BE DRIVEN IN SYNCHRONISM THEREWITH, A SYNCHROTRANSMITTER COUPLED WITH SAID DRIVEN SHAFT FOR PRODUCING AN ELECTRICAL OUTPUT PROPORTIONAL TO THE VELOCITY OF ROTATION OF THE DRIVEN SHAFT, A SYNCHRO-RECEIVER DIRECTLY CONNECTED TO THE ELECTRICAL OUTPUT OF SAID SYNCHRO-TRANSMITTER FOR PRODUCING A MECHANICAL TORQUE OUTPUT PROPORTIONAL TO SUCH ELECTRICAL OUTPUT, A MECHANICAL TORQUE AMPLIFIER DIRECTLY COUPLED WITH THE OUTPUT OF SAID SYNCHRO-RECEIVER AND HAVING MEANS FOR MECHANICALLY AMPLIFYING SUCH OUTPUT, SUCH AMPLIFIER PRODUCING AND AMPLIFIED MECHANICAL TORQUE OUTPUT PROPORTIONAL TO THE OUTPUT OF SAID SYNCHRO RECEIVER AND DIRECTLY COUPLED WITH SAID SECOND SHAFT. 